Tuesday, October 30, 2012

This time, I was curious whether magic find affected the chance of getting gems from mining nodes.*

I've seen plenty of questions about magic find and gathering. I've seen speculation on the topic. I've seen assertions given (many assertions). But the wiki isn't much help. And I haven't seen evidence.

So I set about mining.

Every day for the past two weeks, I took each* of my level 80 characters around Tyria gathering orichalcum and any mithril along the way. All characters used orichalcum mining picks and had the guild gathering bonus. One character had 101% MF, the others only had the guild magic find bonus (10%). By the end, I gathered 1027 mithril and 1483 orichalcum.**

While orichalcum nodes have a higher chance of yielding gems than mithril nodes, I see no difference in the chance of getting gems between 10% MF and 101% MF. (For the stats-nerds, checked with a probit.)

Of course... this is a relatively small sample. So how likely is it that magic find affects the chance of getting gems from mining, but I just didn't notice it? (In stats-language, what is the power of the test, given expectations about the size of the effect being studied.)

To check this, I simulated the results of gathering between 70 to 4200 mining nodes (increments of 70), assuming that magic find works multiplicatively. For each simulation, I checked whether I found that magic find had an effect. (I also included differences between node types, and recorded those.)

From the plot, its clear that after around 1500 mining attempts I'm nearly certain to find an effect from magic find, if one exists. At about 2500 mining attempts (the data I've collected), assuming magic find works, I'd have less than a 1% chance of observing no effect.

* Horray for leveling via crafting. I love going from 10 to 70 in like 2 hours.
** Just to be safe, this data excludes any ruined ore / gems from ruined ore. Which is why neither total is divisible by 3.

As a result, I've salvaged virtually everything I've looted, and recorded the results. This wasn't enough data, so I started buying hundreds of items from the trading post. This left me with a set of just over 4000 salvaged items (predominantly with Basic Kits).

For everything except chests, light and medium armor give an average of two items when salvaged (chests give three). Heavy armor returns about half the items (one item for everything but chests, two from a chest). Two-handed weapons return more items than one handers, which give about the same as offhand weapons.

I don't find any evidence that the number of crafting items salvaged is influenced by

the level of the item (checked visually and via various stats-nerdsy negative binomial regressions)

the rarity of the item (only enough data to test white vs blue at the moment, checked visually and stats-nerdsy)

How good is the salvaged stuff?Each tier of crafting material is salvageable from a range of just under 20 item levels.*

From the graph, its apparent that only some items have a chance to be salvaged into higher-tier crafting components. For example, while a level 18 item can be salvaged into either T1 or T2 crafting components, I've only ever seen lvl 20 items salvage into T2 crafting components.

Excluding T6 materials, I'm getting an approximately 17% chance of getting higher-tier crafting components from salvaging.** The T6 salvage rate seems closer to 10%. I need a bit more data to pin down the chance across tiers / within the level range for each tier.

Important note about salvaging kits: if the bonus percent chance of rarer components from salvaging kits refers to the tier of the crafting material, then using 'better' salvaging kits outside of these level ranges... is probably a waste. (Either the base chance of higher tiers is absurdly low, or it just isn't possible).

I don't find evidence that the tier of the crafting component salvaged is influenced by:

The rarity of the item salvaged. A level 24 item appears to salvage into T2 crafting materials regardless of whether it is blue or white quality. (The probability of salvaging a higher tier also appears approximately equal between the white / blue items.)

The slot of the item (armor / weapon / chest...). More data is needed before this is conclusive, though - I haven't observed some items salvage into the higher tier within some level ranges.

The Unprofitable Salvaging Blues.As noted above, rarity doesn't change the number or tier of crafting items returned or give higher tier materials. As a result, it is often more cost effective to vendor blues and simply buy the desired crafting materials.

Overall, comparing the prices of crafting materials at 11 am on 10/14 to the value of vendoring the item, I lost an average of 7 copper per each blue salvaged, and gained just over 9 copper for each white salvaged (before the AH cut). Factoring in the AH cut, blues were a 12 copper loss to salvage, while whites were a 5 copper gain.

By item level, the level 70-80 blues were the biggest loss to salvage. Middle-level white items were the most profitable.

Next up:
With the basics sorted, the next step is to revisit looking at differences between types of salvaging kits. Unfortunately, this post is getting a bit lengthy, so I'll save more on salvaging kits for a follow-up.

*This graph excludes items salvageable into iron ore, which is both a tier 2 component (as iron) and tier 3 component (refined into steel).
** This is using basic kits. If the chance is multiplicative, this suggests that the salvage rate without kit bonus is around 16%. But that is a topic for another post.

This has caused some problems with my attempts to take a character to level 80 without dying or crafting. Here, for example, is Clawswitz (the Cautious Cowering Charr) standing on top of a vista in Timberline Falls.

Some falls from this tower are perfectly safe, and land you in water. Others send the character to a painful death on the scaffolding below. But that wasn't a big deal. Neither was the champion krait witch at the top of the tower.

The problem was Krait Nimross - level 60 mobs with pull, bleed, immobilize, and knockback. They're strategically placed right at the top of the tower, along the one log you follow to the vista. I took one look, and wondered whether this would be the source of another hilarious death.

Grrrrrr.

Fortunately, Clawswitz survived the vista... by waiting for everything to path away, and being thankful nobody else was around to pull mobs randomly. He's level 65, and very much alive.

Unfortunately, he's also neglected - recently, most of my time online is salvaging or dungeons on my guardian for gold. Hopefully I can find some time to push him the last few levels. (Ideally, time without my ISP dropping out on me randomly. It went down on Saturday while I was killing separatists with Clawswitz. The couple minutes until it came up were... awful.)

Sunday, October 7, 2012

After paying an absurd amount of attention to salvaging rags, something of a consensus has emerged from the official forums, gw2guru, youtube, and reddit on how salvaging kits work. (I'm calling it basic chance theory after Zoodokoo.)

As noted in the reddit thread, one way to account for the minuscule differences in gossamer returns between salvage kits is that instead of increasing the amount of gossamer, the kit modifiers multiplicatively increase the chance for getting gossamer.

So, supposing that gossamer has a base 11% chance of being salvaged from a rag, the chance of getting gossamer with each kit is:Crude: 11% * 1.00 = 11.00%Basic: 11% * 1.10 = 12.10%Fine: 11% * 1.15 = 12.65%Journeyman: 11% * 1.20 = 13.20%Master: 11% * 1.25 = 13.75%As I noted in the reddit thread, this would be entirely consistent with the data I've collected so far.
While it is great to have a theory to test (other than just "everything is consistent with a bug") there are two things that are troubling about this theory.If the theory is correct, then most kits aren't worthwhile (NeckNeckNeck's observation).Supposing gossamer is worth 3.5 silver (350 copper) and silk is worth around 20 copper. So getting 1 gossamer is a gain of about 320 copper. A 1% increase in the chance to salvage gossamer is worth about one hundredth that, or about 3.2 copper. Getting a 1% increase in the chance of getting gossamer compared to crude kits must cost less than 3.2 copper to be worthwhile.

Therefore, assuming the base chance of gossamer is 11%, it is only worthwhile to upgrade to basic kits (for rags).

The bigger trouble is that statistically verifying the theory is going to take absurd amounts of data. The effect sizes here are tiny. As I discussed elsewhere, statistically verifying a tiny effect is tricky business.

Here, I've simulated the results of 1000 different attempts at salvaging 2000 rags, split evenly between crude and mystic kits. For each attempt, I recorded the size of the effect that was estimated and whether it was statistically significant. Sadly, I only find a statistically significant effect 33% of the time. And when I do find an effect, its overestimated.

What does it take to get it right?

Looking at different combinations of kits and sample sizes, its only after 10k salvages, or using absurd amounts of black lion kits, that results can be found reliably and accurately.

I don't even want to think about how much gold that represents. (Dear ANet: can we get a Tyrian NSF going?)

I'm taking a different approach. I've started to collect data on everything I salvage. I'm hoping that I can see a clear pattern where `rare' means 'higher tier of materials'. Hopefully, I'll also find a kind of item with a fairly high chance of being salvaged into the higher tier. This will make for a larger difference between the kits, and therefore something easier to estimate.

I bought 1500 rags from the trading post. Because I apparently have no desire to wear exotics. Ever.

To salvage the rags, I purchased 500 Crude, Basic, and Fine salvage kits. I recorded the number of silk and gossamer from each salvage, and appended this to Signis's data on 500 salvages with Mystic salvage kits.

For reference: Crude kits have no listed chance of giving rare items, a 10% chance for Basic kits, 15% for Fine kits, and 25% for Mystic kits.

So, while crude kits had an 8.6% chance of gossamer, all other kits had a 13% chance.

While it is always possible that I was exceptionally unlucky with crude kits... it is exceptionally unlikely. The probability that I'd observe gossamer 8.6% of the time, when the true chance was 13%... is about 2%. So possible. But not likely.

This contrasts with the claims in this video of "100% certainty" that crude and mystic have identical salvage rates. Hopefully he'll be willing to share the data, and I can take a look at what is going on.

The crude kits leave me a little baffled. Without them, I'd say that gossamer had a 13% chance of being salvaged from a rag and that kits don't matter. With them... kits matter (at least on the choice of crude vs non-crude). But the rate doesn't match what is listed on the item. Hopefully I can salvage these results over the weekend. I've put in more orders for rags to check whether my crude data is just an unlucky draw, and started to collect other salvageable items to check those too.

TLDR: Salvaging rags with Basic, Fine and Mystic kits has a 13% chance of giving gossamer. Crude kits have an 8% chance. More testing required.
Update: I've done another 500 salvages with crude kits... still at about 8.7%. Now going to check other materials. I've decided to make it clearer that the I'm presenting standard errors of the means here, because otherwise I find +/- ambiguous / unfounded.

Monday, October 1, 2012

Sometimes, reading some of the more negative reviews of GW2, I'm convinced the author and I are playing a different game. And its because we are.

"How you play the game can completely change the perception you get of it." The conditioning players have experienced in other MMOs often causes them to miss some of the most amazing bits of GW2. And the game isn't showing them another way to play.

Take combat.

Plenty of MMOs have conditioned players to believe that difficulty is defined by how complex the priority system / rotation is for the class. (Looking at you, feral cat John F* Madden.) MAX DPS is a solo endeavor. Learn a rotation. Do it well. And do it on every single boss. Ok, maybe coordinate some cooldowns from time to time.

So GW2 - where there isn't really a rotation - seems simple. Individual damage can be max'd by hitting 1. Sometimes 2. Keep up buffs. Dodge stuff that hits hard. Stay out of the fire. Standard MMO fare, but with easier button pushing.

But underneath that simplicity is a devilishly complex - and social - difficulty: coordinating combo fields and finishers.

For example, using a blast finisher in a fire field gives might to everyone in the area. So 8 blast finishers = 24 stacks of might (25 is the cap). Which is 720 power / condition damage. Which is about one-third to half of the total power/condition damage of someone stacking that stat. For everyone in the group.

Thing is, one person can't lay down the field and use 8 blast finishers quickly. That takes coordination. So difficulty is now social and coordinated, not individual.

Well, you could do that. But max efficiency? Not so much. While our guild initially thought explorables were a bit rough, learning to use these combos like the devs suggested made runs both easy and short. To be fair, since GW2 does next to nothing to teach players how to effectively use combo fields, its all too easy to dismiss combat as trivial. (I have to look them up.)

The same is true of the game world.

MMOs have conditioned players to expect that the UI will direct them where to go. No talking with NPCs to find hidden stuff. No clicking statues. Definitely no reading. Its a pretty fun way to play. But in GW2, its also a way to miss a ton of really fun stuff.

For me, it took the constant impending peril of death to make me realize GW2 is a little bit different.

I started to notice things, so I went back on my main.

Harathi Hinterlands has a statue. I'd learned from other statues that /kneel can yield buffs. Charr need no gods... but every cat loves its belly scratched.

So I light the candle, and kneel. Ghost pops up, tells a cool story, and directs me to start an event. Event is awesome! And just sitting there. Waiting for anyone ready to observe the world around them. (Cara Emm's video above does so much more to detail this.)

Its not just events. Its all those vendors I've been ignoring. Fleetze has a great post listing some fun and useful consumables found around the world. Summonable ranger pets for all. Instant vanish. Knockdowns. Fire fields. I'm probably going to lose half my gold porting to every vendor in the game and clicking the junk they have for sale, just to see if its actually useful. Oh goodness, did I just become a skritt?

For just for a little more willingness to explore, I've found so much more depth to the game.

Time for some sage quaggan advice:

ooooOOOOoooo Quaggan thinks you should smell the roses, maybe? ooooOooOOOOooo